New research has shown that the current weight loss ‘rule of thumb’ of cutting daily caloric intake by 500 calories is not enough for continued weight loss. People have used this rule of thumb for how to lose weight for decades and it turns out to be flawed because it doesn’t take into account metabolic changes that take place when people change their diet. To get a more accurate prediction of how much weight an individual will lose on a specific diet and exercise regime, as well as to better understand the physiology of weight loss, scientists are now using mathematics.
The old rule of thumb is overly optimistic, as it doesn’t take into account metabolism slowing during dieting. Researchers at the National Institutes of Health have now come up with a formula that accounts for height, weight, age and physical activity level to better predict how much weight an individual may lose on a diet and exercise plan. From their research, they also came up with a better rule of thumb for weight loss: Cut 10 calories per day from your diet for every pound you want to lose over a three-year period. This means that if the goal is to lose 10 pounds over 3 years, 100 calories would need to be cut per day. The researchers noted that half of the weight loss would occur over the first year and to shed more weight after the three-year increment, calorie intake would need to be further reduced.
Researcher, Kevin Hall, explained that the new model might help policy makers understand the impact of public health measures on the obesity epidemic. For example, an estimate of the result of a 20% tax on sugary beverages predicted that the tax would lead to a 50% decrease in the number of overweight people in America in five years. While, according to Hall, the new model predicts approximately a 5% decrease in the percentage of overweight people in the same time period. Currently, the model is intended only for use by physicians and scientists. The research was presented at the annual meeting of the American Association for the Advancement of Science last month. You can read more about the math behind measuring body weight here, in an article about potential alternative measurements to Body Mass Index (BMI).
Expert bariatric surgeon, Dr. Gregory Walton of the WeightWise Bariatric Program, commented on the new research. He said, “The researchers at the National Institutes of Health are using predictive math to objectify what doctors treating obesity have subjectively experienced for years: Dramatically chasing calories down as a method of weight loss is fraught with eventual failure. The laws of thermodynamics seemingly make the weight-loss equation simple: calories in < calories out = weight loss. The problem: our body’s metabolic engine is not a constant calorie burning machine; in fact the rate of burn varies in response to the energy intake, the composition of the intake, the timing of the intake, environmental factors and hormonal factors. Another nebulous (but very important) factor in the undermining of simple thermodynamics is hunger. Dramatically lowering calorie intake stimulates hunger. Support in the literature exists: hunger hormones rise in response to continued calorie lowering.”
Dr. Walton explained that “at the end of the day, obesity is a disease of inappropriate hunger in the face of excessive calorie storage. Applying logic then, chasing hunger down (instead of calories) is potentially a more successful goal. Unfortunately abnormal hunger is a multifactorial disease state with biological, psychological and sociological contributions. We have learned from weight loss surgery: the psychosocial hunger is not the predominant factor in the disease of obesity (as popular belief holds); instead, the biologic hunger apparently overwhelms the psychosocial hunger in the obese population. Post op weight loss surgery patients have dramatic decrease in hunger immediately after the operation, supporting biologic hunger as the main culprit to ineffective weight loss.” Dr. Walton concluded that it would be hard to imagine a better use of resources than investing in prevention and treatment strategies for obesity, as obesity is the root cause of up to 30 other diseases. “If current trends hold, the physical . . . and the financial health of the country may well depend on the prevention and treatment of obesity,” he concluded.
Nutrition & Lifestyle